University of Konstanz
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YOLO‐Behaviour : A simple, flexible framework to automatically quantify animal behaviours from videos
No full text1. Manually coding behaviours from videos is essential to study animal behaviour but it is labour‐intensive and susceptible to inter‐rater bias and reliability issues. Recent developments of computer vision tools enable the automatic quantification of behaviours, supplementing or even replacing manual annotation. However, widespread adoption of these methods is still limited, due to the lack of annotated training datasets and domain‐specific knowledge required to optimize these models for animal research.
2. Here, we present YOLO‐Behaviour, a flexible framework for identifying visually distinct behaviours from video recordings. The framework is robust, easy to implement, and requires minimal manual annotations as training data. We demonstrate the flexibility of the framework with case studies for event‐wise detection in house sparrow nestling provisioning, Siberian jay feeding, human eating behaviours and frame‐wise detections of various behaviours in pigeons, zebras and giraffes.
3. Our results show that the framework reliably detects behaviours accurately and retrieve comparable accuracy metrics to manual annotation. However, metrics extracted for event‐wise detection were less correlated with manual annotation, and potential reasons for the discrepancy between manual annotation and automatic detection are discussed. To mitigate this problem, the framework can be used as a hybrid approach of first detecting events using the pipeline and then manually confirming the detections, saving annotation time.
4. We provide detailed documentation and guidelines on how to implement the YOLO‐Behaviour framework, for researchers to readily train and deploy new models on their own study systems. We anticipate the framework can be another step towards lowering the barrier of entry for applying computer vision methods in animal behaviour.publishe
Activist disciplines : Universities in autocracies and political protest
No full textRecent events on university campuses show again that academic institutions often constitute breeding grounds for political mobilization. This also applies to autocratic countries, where political protest has been found to be more likely to occur in university cities. However, research so far has failed to address the question of which universities are more likely to see protest. In this paper, we focus on the disciplinary composition of universities in autocracies. We argue that non-STEM disciplines traditionally attract more progressive students, cover more politically sensitive topics, and oftentimes study the determinants of successful mobilization. Therefore, they should be more likely to serve as focal points for political protest. We test our expectations in a large-scale comparative analysis, using fine-grained data on the composition and location of academic institutions in autocracies combined with event data on political protest. We find that political activism is more likely in cities with institutions focused on arts and humanities, which points to the potentially transformative role of these disciplines even in severely constrained political settings.publishe
Autonomie und Institution : Frauenbewegung und Frauenforschung in der Bundesrepublik (1976-1982)
No full textpublishe
Naturalized alien plants experience less negative soil‐legacy effects and gain competitive advantages through spatial heterogeneity
No full text1. With the number of naturalized alien plant species continuously increasing, it has become of major interest to understand how they can coexist with or even outcompete native species. Plant–soil interactions and soil spatial heterogeneity are thought to play major roles in the coexistence of plant species. Depending on the strengths of conspecific and heterospecific soil feedbacks, size inequalities between competing plants might either decrease (i.e. promote coexistence) or increase. However, how spatial heterogeneity in soil legacies affects individual growth, competitive balance and thus coexistence of competing plants, and how this depends on the plant origins has never been tested.
2. Here, we first conditioned soil with each of five naturalized alien and five native species separately. Thereafter, we grew all 45 pairwise species combinations under four homogeneous soil-legacy conditions (including unconditioned soil as one of the homogeneous conditions) and two heterogeneous soil-legacy conditions.
3. Soil legacies overall had a negative effect on biomass production, irrespective of the origins of the competing species. Biomass inequality between the competing plants was the smallest when they grew on soil conditioned only by the larger one of the two species. Both alien and native plants suffered strongly from conspecific soil legacies. However, alien plants could benefit from another co-growing alien species on homogeneous-conspecific soil, which thus mitigated negative soil-legacy effects, or benefit from heterogeneous soil conditions to increase the competitive advantage over native plants.
4. Our findings show that the performance of competing plants may depend on their origins as well as on soil legacies. This may ultimately affect species competition and coexistence in natural environments where soil legacies are likely to be heterogeneous.publishe
When multilingualism is more than three : On the nature of gender transfer in L3+ acquisition
No full textIn this article we investigate transfer in the ab-initio acquisition of grammatical gender in two groups of multilingual learners. The first group knows two gender languages (German and French), which can potentially act as transfer sources; the second group knows three (German, French and Italian). Both groups had to assign gender to nouns in Franco-Provençal, a Romance language which is new to the learners, and which shares similarities with both French and Italian. Based on our data, we address the question whether there is a unique transfer source and what the respective roles of sub-lexical structural similarity, proficiency, and recency of use of the background languages are. The findings of this study reveal that learners of the first group use both French and German as transfer sources, whereas learners in the second group additionally transfer from Italian. We show that the amount of transfer increases with higher proficiency, more recent use of the source language(s), and increasing structural similarity between the source and target language. Finally, not only is the gender feature transferred but also orthographical cues.publishe
Generalised power series determined by linear recurrence relations
No full textIn 1882, Kronecker established that a given univariate formal Laurent series over a field can be expressed as a fraction of two univariate polynomials if and only if the coefficients of the series satisfy a linear recurrence relation. We introduce the notion of generalised linear recurrence relations for power series with exponents in an arbitrary ordered abelian group, and generalise Kronecker's original result. In particular, we obtain criteria for determining whether a multivariate formal Laurent series lies in the fraction field of the corresponding polynomial ring. Moreover, we study distinguished algebraic substructures of a power series field, which are determined by generalised linear recurrence relations. In particular, we identify generalised linear recurrence relations that determine power series fields satisfying additional properties which are essential for the study of their automorphism groups.publishe
Spaceborne and UAV-LiDAR reveal hammer-headed bat preference for intermediate canopy height and diverse structure in a Central African rainforest
No full textBackground
Animals with key ecological roles, such as seed-dispersing fruit bats, rely to varying degrees on habitat structure to indicate the locations of resources and risks.
Methods
To understand how variation in vegetation structure influences fruit bat habitat selection, we related movement steps of hammer-headed bats (Hypsignathus monstrosus) to attributes of canopy height, vertical and horizontal vegetation structure, and habitat type in a mature rainforest of southern Cameroon. Vegetation structural metrics were measured with UAV-LiDAR at 10 m resolution for a 25 km2 study area. Because bats frequently moved outside the study area, we also characterized vegetation height and horizontal complexity over the full extent of bat movement trajectories by upscaling UAV-LiDAR measurements using primarily GEDI LiDAR data.
Results
At the site level, hammer-headed bats preferred areas of intermediate canopy height (13.9–32.0 m) close to large canopy gaps (≥ 500 m2). Individual bats varied in selection for vertical vegetation complexity, distance to smaller canopy gaps (≥ 50 m2) and plant volume density of intermediate vegetation strata (10–20 m). Over the full extent of movement trajectories, hammer-headed bats consistently preferred intermediate canopy height, and areas closer to canopy gaps. At both spatial extents, bats moved the shortest distances in swamp habitats dominated by Raphia palms. These behaviors indicate the use of forest types that vary structurally, with a preference for open airspace during foraging or moving among resources, and for dense swamp vegetation during roosting and resting periods. In addition, most bats regularly made long flights of up to 17.7 km shortly after sunset and before sunrise and limited their movements to three or fewer destinations throughout the tracking period.
Conclusions
These results highlight the importance of structurally diverse landscapes for the nightly movements of hammer-headed bats. Our results show how remote sensing methods and animal tracking data can be integrated to understand habitat selection and movement behavior in tropical ecosystems.publishe
Lophine analogues as fluorophores for selective bioimaging of the endoplasmic reticulum
No full textThe design of small-molecule fluorescent probes for labelling the endoplasmic reticulum (ER) revolves around a well-established albeit limited group of structural architectures. Here, we synthesized new fluorescent lophines in one step in high-temperature water (HTW) and explored their application as dyes for selective bioimaging of the ER.publishe
Thermodynamic properties of a superconductor interfaced with an altermagnet
No full textRecently introduced magnetic materials called altermagnets (AM) feature zero net magnetization but a momentum-dependent magnetic exchange field, which can have intriguing implications when combined with superconductivity. In our work, we use the quasiclassical framework to study the effects of such a material on a conventional superconductor (S) in an AM/S bilayer. We discuss the superconducting phase diagram and heat capacity of AM/S while making a comparison with a ferromagnet-superconductor bilayer. Furthermore, we examine the density of states and analyze the system's response to an external magnetic field. We illustrate the anisotropy of spin susceptibility and magnetization of AM/S by considering an external field in the in-plane and out-of-plane directions, thereby facilitating the scope of experimental detection and characterization of an AM in an AM/S hybrid system.publishe